Automatic lathe comprising at least two radial tool-holders



P. BERGONZO May 10, 1966 AUTOMATIC LATHE COMPRISING AT LEAST TWO RADIALTOOL-HOLDERS Filed March 12, 1964 2 Sheets-Sheet 1 y 0, 1966 P. BERGONZC3,250,159

AUTOMATIC LATHE COMPRISING AT LEAST TWO RADIAL TOOL-HOLDERS Filed March12, 1964 2 Sheets-Sheet 2 United States Patent Claims: 01. 8225) Thepresent invention has for an object provision of an automatic lathecomprising at least two radial tool-holders sliding in guides carried bythe front face of the headstock and the radial movements of which arecontrolled by a cam-shaft through the agency of transmission membersincluding two feelers cooperating with the profile of at least one cam,characterized by the fact that these transmission members furtherinclude a single chain of mechanical members connecting the said twofeelers to a single actuating member controlling positively (drivingly)the movements of the said radial tool-holders in their forward movementand sensitively (resiliently) in their backward movement.

The accompanying. drawing shows diagrammatically and by way of exampleone embodiment of the present invention. I

FIG. 1 is an end view of the lathe, certain parts being seen in sectionshowing the control of the radial toolholders object of the invention.

FIG. 2 is a section along line IIII of FIG. 1.

FIG. 3 is a section along line III-III of FIG. 1.

Referring to the drawing the automatic lathe comprises a frame 1, aspindle 2 pivoting in a headstock 3 fixed on the frame of the lathe andtwo radial tool-holders 4, 5

sliding in guides (not shown) carried bythe front face of the headstock3. The radial movements of these toolholders are controlled by acam-shaft 6, driven to rotate in known manner by a motor (not shown),through the agency of trans-mission members including at least one camcarried by the cam-shaft 6 cooperating with two feelers and a singlechain of mechanical members connecting the said two feelers to anactuating member controlling the movements of the said radialtool-holders 4, 5 positively (drivingly) during their forward movementand sensitively (resiliently) during their backward movement.

In the embodiment shown in the drawing the cam-shaft 6 carries twocams7, 8 angularly offset one with respect to the other and eachcooperating with a feeler 9, 10 both rigidly connected by arms 11, 12 toa toothed sector 13 pivoting on a shaft 14 rigidly secured to a lug 15of the frame 1. These feelers 9, 10 are each in contact with one of thecams 7, 8 thus determining the angular position of the toothed sector 13dependent on the angular position of the cam-shaft 6. The toothed sector13 meshes with a rack 16 carried by one of the ends of a connecting bar17 disposed vertically and extending across the headstock 3. Thisconnecting bar 17 slides inside the headstock 3 but its angular positionrelative to this headstock is fixed. The upper end of this connectingbar carries a rack 18 in mesh with a toothed sector 19 integral with ashaft 20 pivoting on the headstock 3. This connecting bar 17 thus drivesthe toothed sector 19 through angular movements depending on those ofthe toothed sector '13, these angular movements are therefore dependenton the rotation of the cam-shaft 6.

This toothed sector 19 drives, in its angular oscillations,

an actuating member 21 also rigidly fixed to the shaft 20. Thisactuating member comprises two thrust members 22, 23 disposedsymmetrically on either side of the shaft 20. Each of these thrustmembers 22, 23 is situated on the path of the upper end 24, 25 of a rack26, 27 sliding freely in the headstock 3. The teeth of these racks3,250,159 Patented May 10, 1966 26, 27 mesh with a corresponding pinion28, 29 pivoting on the headstock 3 and in gear with toothings 30, 31carried by the corresponding radial tool-holder 4, 5.

i The radial tool-holders 4, 5 are each subjected to a resilient returnaction, constituted by a spring 32, 33 in the example shown, tending toretain these tool-holders in their return travel end stroke position.This return travel end stroke position is determined by means of anadjust-- able abutment 34, 35 rigidly fixed to the headstock 3.

In the figure of the drawing the two radial tool-holders 4, 5 are heldin the return travel end stroke position by means of the springs 32, 33so that the racks 26, 27 are held in their high position and the upperends 24, 25 of each of them is in contact with the corresponding thrustmember 22, 23 of the actuating member 21 which is in a neutral orhorizontal rest position.

The operation of the control device for the radial toolholders describedis the following:

Each of the cams 7, 8 is constantly in contact with the correspondingfeeler 9, 10 so that the toothed sector 13 is maintained positively, inthe two directions, in an angular position determined by the angularposition of the cam-shaft 6.

When, from the neutral or rest position shown, the toothed sector 13moves angularly in the direction of the arrow 1 for example, as a resultof a rotation of the camshaft 6, this toothed sector drives, through theagency of the connecting bar 17, the toothed sector 19, through anangular movement in the same direction.

The angular movement of the toothed sector 19 causes, through the agencyof the shaft 20, a similar angular movement of the actuating member 21.

The pivoting of the actuating'mernber 21 in the direction of the arrow gbrings about the downward movement of the rack 27 through the agency ofthe thrust member 23 which causes the pinion 29 to rotate driving in itsturn the toothing 31 carried by the tool-holder 5 in the direction ofthe arrow h. The tool-holder 5 is thus moved towards the work-piece in aforward travel against the action of its return spring 33. r

This tool-holder 5 is thus actuated positively in its forward movementby an amount determined by the shape of the cams 7, 8 carried by thecam-shaft 6 and corresponding to the machining operation to be effected.

Then, once the forward travel end stroke position of the tool-holder 5has been reached, the angular movement of the sector 13, driven by thecams 7, 8 cooperating with the feelers 9, 10 changes direction and movesin the reverse direction of the arrow 3 which brings about, alwaysthrough the agency of the connecting bar 17 of the toothed sector 19 andof the shaft 20, an angular movement of the actuating member 21 in adirection the reverse of that of the arrow g.

As from this moment, the backward travel of the toolholder 5 is startedand the same is controlled sensitively, the rack 27 being appliedagainst the thrust member 23 of the actuating member 21 throughtheaction of the return spring 33, until the said tool-holder 5 reachesthe end of its backward travel at which it rests on its adjustableabutment 35 and at which the actuating member 21 is in the neutral orhorizontal rest position.

During .all this time, forward and backward travel of the tool-holder 5,the tool-holder 4 remains in its backwar-d travel end stroke position,held against its adjustable abutment 34 through the action of the returnspring 32. Indeed, during the angular movement of the actuat ing member21 in the direction of the arrow g from its neutral rest position, thethrust member 22 leaves the front face of the end 24 of the rack 26, thehigh position of the latter being determined by the adjustable abutment34.

Then, when the actuating member 21, driven by the cams 7, 8, continuesto move in the reverse direction to that of the arrow g but overstepsits neutral rest position, the thrust member 22 actuatcs the rack 26 ina downward direction and thus =causes,-through the agency of the pinion28 and of the toothing 30, the forward travel of the tool-holder 4against the action of its return spring 32. Finally, when thetool-holder 4 has reached its forward travel end' stroke position,determined by the cams 7, 8, the angular movement of the sect-or 13 andtherefore of the actuating member changes direction and the toolhol-dereffects its backward travel under the action of its return springtending to push the upper part 24 of the rack 26 against the thrustmember 22. Finally, when the tool-holder 4 reaches the end of itsbackward travel, determined by its adjustable abutment 34, the actuatingmember 21 is again in its neutral rest position.

Here again, as for the tool-holder 5, the tool-holder 4 is actuated inits forward travel and sensitively in its backward travel.

In the example shown, the adjustable abutments 34, 35 determining thebackward travel end stroke position of the tool-holders 4, are adjustedso that these two radial tool-holders are never simultaneously inmotion. Indeed,

'when one of them moves, the other is maintained at rest against itsbackward travel end stroke abutment. However, for other adjustments ofthese end stroke abutments, for example when the backward travel endstroke position of the tool-holder does not correspond to the neutralrest position of the actuating member 21, it is possible that during apartof the cycle of the movement of one of the tool-holders, the othertool-holder is also in motion.

In any case, this control device for the radial toolholders of anautomatic lathe permits of reducing, practically by half, the travels ofthe said radial tool-holders relative to existing devices in which thesaid tool-holders are constantly simultaneously in motion in oppositedirections one with respect to the other.

This reduction of the travel of the radial tool-holders 4, 5 attributesto the automatic lathe according to the invention appreciable advantagesof which the principal ones are:

(a) Reduction of the bulkness of the lathe which is very important.

(b) As a result, it is no longer possible to uncover, during thebackward travel of the tool-holders, the slides of these tool-holders sothat these slides are no longer exposed to shavings or other fragmentswhich may give rise to jamming of the tool-holders or a very pronouncedwear of these slides.

I claim:

1. An automatic lathe comprising at least two radial tool-holderssliding in guides carried by the front face of the headstock and theradial movements of which are controlled by a cam-shaft through theagency of trans mission members including two feelers cooperating withthe profile of at least one cam, in which these transmission membersfurther include a single chain of mechanical members connecting the saidfeelers to a single actuating member which is movable angularly about anaxle perpendicular to the front faces of the headstock and comprises twothrust members disposed symmetrically on either side of the said axle,said actuating member drivinglyc-ontrolling the movements of the radialtool holders during their forward movement and resiliently during theirbackward movement.

2. An automatic lathe comprising at least two radial tool-holderssliding in guides carried by the front face of the headstock and theradial movements of which are controlled by a cam-shaft through theagency of transmission members including two feelers cooperating withthe profile of at least one cam, in which these transmission membersfurther include a single chain of mechanical members connecting the saidfeelers to a single actuating member which is movable angularly about anaxle perpendicular to the front faces of the headstock and comprises twothrust members disposed symmetrically on either side of the said axleand located on the path of a rack meshing with a pinion in gear with atoothing carried by the corresponding tool-holder, said actuating memberdrivingly controlling the movements of the radial tool holders duringtheir forward movement and resiliently during their backward movement.

3. An automatic lathe comprising at least two radial tool-holders eachof which is subjected to a flexible return action tending to maintain itin its backward end stroke position determined by an adjustable abutmentfixed on the headstock, said tool-holders sliding in guides carried bythe front face of the headstock and the radial movements of which arecontrolled by a cam-shaft through the agency of transmission membersincluding two feelers cooperating with the profile of at least one cam,in which these transmission members further include a single chain ofmechanical members connecting the said feelers to a single actuatingmember which is movable angularly about an axle perpendicular to thefront faces of the headstock and comprises two thrust members disposedsymmetrically on either side ofthe said axle, said actuating memberdrivingly controlling the movements of the radial tool-holders duringtheir forward movement and resiliently during their backward movement.

4. An automatic lathe comprising at least tWo radial tool-holderssliding in guides carried by the front face of the headstock and theradial movements of which are controlled by a cam-shaft through theagency of transmission members including two feelers cooperating withthe profile of at least one cam, in which these transmission membersfurther include a single chain of mechanical members connecting the saidfeelers to a single actuating member which is movable angularly about anaxle perpendicular to the front faces of the headstock and comprises twothrust members disposed symmetrically on either side of the said axleand located on the path of a rack meshing with a pinion in gear with atoothing carried by the corresponding tool-holder, said thrust membersand rack being constructed and arranged so that during movement of oneof the tool-holders only one of the thrust members is in contact withits corresponding rack, said actuating member drivingly controlling themovements of the radial tool-holders during their forward movement andresiliently during their backward movement.

5. An automatic lathe comprising a headstock, guides carried by theheadstock, first and second radial toolholders slidable in said guides,a single angularly moveable actuating member for actuating both saidradial toolholders, a cam-shaft, feelers cooperating with the camshaftprofile, a single chain of mechanical members connecting said feelersand said angularly movable actuating member to positively controlmovement of one of said radial tool-holders towards a workpiece, andresilient means controlling the reverse movement of the other of saidtool-holders while said one of said tool-holders moves towards theworkpiece.

5. AN AUTOMATIC LATHE COMPRISING A HEADSTOCK, GUIDES CARRIED BY THEHEADSTOCK, FIRST AND SECOND RADIAL TOOLHOLDERS SLIDABLE IN SAID GUIDES,A SINGLE ANGULARLY MOVEABLE ACTUATING MEMBER FOR ACTUATING BOTH SAIDRADIAL TOOLHOLDERS, A CAM-SHAFT, FEELERS COOPERATING WITH THE CAMSHAFTPROFILE, A SINGLE CHAIN OF MECHANICAL MEMBERS CONNECTING SAID FEELERSAND SAID ANGULARLY MOVABLE ACTUATING MEMBER TO POSITIVELY CONTROLMOVEMENT OF ONE OF SAID RADIAL TOOL-HOLDERS TOWARDS A WORKPIECE, ANDRESILIENT MEANS CONTROLLING THE REVERSE MOVEMENT OF THE OTHER OF SAIDTOOL-HOLDERS WHILE SAID ONE OF SAID TOOL-HOLDERS MOVES TOWARD THEWORKPIECE.